The present application relates to a semiconductor structure and a method of forming the same. More particularly, the present application relates to a semiconductor structure including an ordered array of parallel graphene nanoribbons, a method of forming such a structure, and a semiconductor circuit including at least one semiconductor device that can be formed on the ordered array of parallel graphene nanoribbons.
Several trends presently exist in the semiconductor and electronics industry including, for example, devices are being fabricated that are smaller, faster and require less power than the previous generations of devices. One reason for these trends is that personal devices such as, for example, cellular phones and personal computing devices, are being fabricated that are smaller and more portable. In addition to being smaller and more portable, personal devices also require increased memory, more computational power and speed. In view of these ongoing trends, there is an increased demand in the industry for smaller and faster transistors used to provide the core functionality of the integrated circuits used in these devices.
Accordingly, in the semiconductor industry there is a continuing trend toward fabricating integrated circuits (ICs) with higher densities. To achieve higher densities, there has been, and continues to be, efforts toward down scaling the dimensions of the devices on semiconductor wafers generally produced from bulk silicon. In order to accomplish these trends, high densities, smaller feature sizes, smaller separations between features, and more precise feature shapes are required in integrated circuits (ICs). These trends are pushing the current technology to its limits.
In view of the above, the semiconductor industry is pursuing graphene to achieve some of the aforementioned goals. Graphene, which is essentially a flat sheet of carbon atoms, is a promising material for radio frequency (RF) transistors and other electronic devices. Typical RF transistors are made from silicon or more expensive semiconductors such as, for example, indium phosphide (InP).
With all its excellent electronic properties, graphene is missing a bandgap, making it unsuitable for fabrication of digital devices. Transistors fabricated using graphene in the channel would have Ion/Ioff ratios of the order of 10 or less, with many more orders of magnitude still required for proper function of such devices. It has been shown that bandgaps can be created in graphene if fabricated in the form of nanoribbons. The size of the bandgap increases with decreasing width of the nanoribbon and for potential practical digital applications the width of the graphene nanoribbons (GNR) has to be less than 10 nm, preferably less than 5 nm.